Draw two concentric circles of radii 4 cm and 6 cm. Construct a tangent to the smaller circle from a point on the larger circle. Measure the length of this tangent.
Steps of Construction:
1. With O as a center, draw a circle of radius of 4cm and another circle of radius 6cm.
2. Mark any point A on the bigger circle.
3. Join OA. Draw perpendicular bisector of OA.
4. The perpendicular bisector XY of OA intersects OA at B.
5. With B as center and radius of length OB (or BA), draw a circle.
6. This circle intersects the smaller circle(of radius 4cm) at P and Q.
7. Join AP and AQ.
8. Then AP and AQ are the required tangents.
9. The measured length of AP and AQ is 4. 4cm (approximately).